1. Field of the Invention
The present invention relates to a position information encoding apparatus and a method thereof, a position information decoding apparatus and a method thereof, and a map information processing apparatus and a method thereof suitable for searching map information and related information through the Internet.
2. Description of the Related Art
The Internet has a service called WWW (World Wide Web) that allows a user to search multimedia information through the network thereof with hypertext that links text information, image information, audio information, and so forth. With the WWW, various types and huge amounts of information including shopping information and restaurant information are provided. In addition, home pages of the WWW are being published by public organizations (such as governments and local governments), small companies, small stores, and individuals. It is expected that services using the WWW will drastically grow in the future.
With services of the WWW, the user can easily obtain shopping information, event information, and so forth. However, to get to stores and event places corresponding to the obtained information, the user needs to obtain position information thereof. To provide the user with shopping information and event information on the WWW, it is necessary to add information of the locations of the stores and event places.
To do that, WWW pages may have map information of the locations of event places and stores. Since the WWW can handle hypertext, maps of the locations of the stores and event places can be published as map information. When the maps of the locations of the stores and event places are published as image information, the user can reference the map information to get to the desired store and event place.
However, the roads and geographical structures are very complicated. Thus, it is very troublesome for publishers of WWW pages to draw maps for the stores and event places and to paste them to relevant pages. In addition, new roads and buildings are being built and old buildings are being demolished day by day. Thus, the roads and buildings are being changed day by day. In other words, the maps that the publishers of the WWW pages drew may be inaccurate when the user sees them.
In addition, information that represents the locations of event places and stores (for example, latitude information and longitude information thereof) may be placed in such WWW pages. With the latitude information and longitude information, the user can get to the desired event places and stores with reference to the maps. Alternatively, application programs of personal computers and car navigation systems that display maps corresponding to latitude information and longitude information that users input are known. Thus, with such application programs and car navigation systems, the users can search locations on maps with the latitude information and longitude information.
However, it is very troublesome for the users to check out the locations of the event places and stores on the maps with the latitude information and longitude information. In addition, to search the event places and stores with the latitude information and longitude information, the latest and accurate maps should be prepared. With the application programs of the personal computers and the car navigation systems, the users can search the positions of the event places and stores on the maps with the latitude information and longitude information. However, such application programs and car navigation systems are expensive and difficult to deal with changes of roads and buildings.
To solve this problem, a WWW site that provides users with a map information service that searches a map corresponding to input position information and displays the position on the map may be provided on the Internet. With such a WWW site, a user who obtained a store or an event place from a relevant WWW page can easily know the position thereof on the map. In addition, since such a WWW site constantly updates map data, it can deal with changes of roads and buildings.
Such a WWW site that provides the user with map information may use latitude information and longitude information as position information. The latitude represents the angular distance north or south from the earth's equator measured through 90 degrees. The southern hemisphere of the earth is referred to as south latitude, whereas the northern hemisphere of the earth is referred to as north latitude. The longitude represents the angular distance, along the Equator, between the meridian passing through a position and, usually, the meridian of Greenwich. The eastern part of the earth is referred to as east longitude, whereas the western part of the earth is referred to as west longitude. The position information using the latitude and longitude has been generally employed for a long time.
However, it is not always said that latitude information and longitude information are the best as position information. In other words, when a user inputs position information with the keyboard, the information should be represented by a small number of codes. If the position information is represented by a small number of codes, when the user exchanges position information with others by electronic mail, telephone or the like, he or she can easily memorize it. Thus, the user can correctly input the position information without mistakes. However, the latitude information and longitude information are composed of many codes. Thus, the users tend to input the latitude information and longitude information with mistakes.
When the position of S Company is represented in the accuracy of 0.1 second, the position is at north latitude 35.degree., 37', 13.5" and east longitude 139.degree., 44', 9.6". When the user inputs the latitude information and longitude information, he or she should input 24 characters "N 35.degree. 37' 13.5" E 139.degree. 44' 9.6".
In addition, so far, the notation of latitude information and longitude information has not been internationally defined. In other words, the abbreviations and order of east longitude, west longitude, north latitude, and south latitude have not been standardized. In addition, since the latitude information and longitude information does not have an error detection code and/or a correction code, they do not deal with errors.